Bleeding during pregnancy and delivery There are not enough data on the risks of pregnancy and delivery of the female patients with moyamoya disease. It has been believed that such risks are not high in spite of the history of bypass surgery. To my best knowledge, there have been three such cases reported. This means that there is a potential risk, although not high enough, in the pregnancy for the patients with moyamoya disease. Three cases reported with poor outcome Case 1: A 23-year-old patient, who was diagnosed as moyamoya at the age of 10. She developed bilateral ventricular hemorrhage at 30 weeks of gestation. The child was normally delivered but the patient had severe consciousness disturbance. (Shimamoto, 1994) Case 2: Woman in her twenties developed intracerebral hemorrhage during spontaneous, but delayed delivery. Caesarian section was performed in emergency. The child was normal, but the patient died. This patient developed ischemic event when she was a child, and moyamoya disease was diagnosed at that time. She did not undergo bypass surgery, but no ischemic events recurred at least several years before her pregnancy. Case 3: Age of the patient was not specified. She developed ischemia when she was a child. Within a year, she underwent bilateral EDAS surgery (indirect bypass). Twenty years later, (19 years after bypass surgery), she developed ventricular hemorrhage at 30 weeks of gestation and died. (Nakagawa, 2003) 2004.2.8